$8B salmon recovery failure

This 60-Minutes story makes it clear that removal of the four lower Snake River dams makes fiscal sense to the American tax-payer. As an oceanographer, however, I’m intrigued with how little seems to be known about how the salmon fare in the ocean. Along with the dams, land-use, and pollution, the other major potential impacts on salmon survival are marine: fishing and other oceanic variability.

A comment on the story caught my attention, for it suggested comparing run dynamics on dam-free rivers as a way to assess the importance of the marine impacts. Now I wish such a comparison was readily available to me… I’ll start searching! Holler if you know of one.

Another approach would be to juxtapose the Snake River returns with some independent measures of oceanic conditions that prevailed when the returning fish inhabited the ocean. Station Papa in the mid-northeast-pacific would be a good place to start. More-coastal buoys and transects could ensure that spatial heterogeneity isn’t an issue. Of course, this begs the question of where Columbia basin salmon go in the sea. With that pinned down we could attempt population assessments in situ (hydroacoustic surveys?) to assess mortality along migration pathways, and finally overlay commercial catch data and geography to see if harvest matters for particular salmonids.